What is the difference between a conductor and an insulator?

What is the difference between a conductor and an insulator?

• A. A conductor easily allows electric charges to move; an insulator resists charge flow.
• B. An insulator easily allows electric charges to move; a conductor resists charge flow.
• C. A conductor blocks current completely.
• D. An insulator conducts electricity as well as a conductor.

Answer: (A)

Charges move differently in different materials. A conductor has many free charge carriers that can respond to an electric field and drift, so charges flow easily when a potential difference is applied. An insulator holds its electrons tightly to atoms, so there are few free carriers and the flow of charges is strongly resisted. That’s why metals like copper are used for wires—to carry current efficiently—while plastics or rubbers are used as insulation—to prevent current from escaping or touching other surfaces. Saying that a conductor allows charge to move easily and an insulator resists charge flow captures the essential contrast in how readily charges can travel through each type of material. Real materials aren’t perfect either way, but this distinction is the practical basis for designing circuits and protecting people and devices.

Charges move differently in different materials. A conductor has many free charge carriers that can respond to an electric field and drift, so charges flow easily when a potential difference is applied. An insulator holds its electrons tightly to atoms, so there are few free carriers and the flow of charges is strongly resisted. That’s why metals like copper are used for wires—to carry current efficiently—while plastics or rubbers are used as insulation—to prevent current from escaping or touching other surfaces. Saying that a conductor allows charge to move easily and an insulator resists charge flow captures the essential contrast in how readily charges can travel through each type of material. Real materials aren’t perfect either way, but this distinction is the practical basis for designing circuits and protecting people and devices.